It is known to carry out the deicing of surfaces prone to icing with the aid of heated air that originates, for example, from main engines or from an auxiliary power unit (Auxiliary Power Unit, APU) and is usually routed through a deicing valve, a throttling element and a piccolo tube that is respectively situated in the interior of the wing nose or slats (slats). The hot engine bleed air escapes through the openings of the piccolo tube and flows directly along an underside or inner side of a surface prone to icing, to which it transfers part of its thermal energy. Due to the high energy content of the hot bleed air obtained from the main engines, an internal wing deicing system of an aircraft realized in accordance with the prior art can only be utilized in-flight because material overheating of the wing structure may easily occur on the ground due to the lack of relative wind.
EP 1 935 783 B1 and EP 1 116 656 B1 disclose thermal deicing devices and methods by means of hot air. US 20080105217 A1 discloses a thermal deicing system that operates with water-saturated, heated air while U.S. Pat. No. 6,848,656 B2 proposes to remove molten ice with an air current acting thereupon. DE 10 2008 019 146 A1 proposes to heat air that originates, for example, from a passenger cabin by means of a fuel cell and to route this heated air into regions of the aircraft to be deiced. DE 10 2006 002 882 B4 and DE 10 2004 058 430 B4 mention the thermal wing deicing by means of the waste air flow from a fuel cell or fuel cell waste gas, respectively. With respect to an evaporatively cooled fuel cell system, EP 2 225 789 B1 describes the advantages of the heat transfer by means of a change in state of aggregation in comparison with the heat transfer by means of hot air. EP 1 973 780 B1 proposes to counteract material damages due to overheating by improving the heat transmission due to an increase of the air turbulence on the wing nose. EP 1 793 013 B1 proposes to prevent material overheating by means of a mixing chamber.
Despite the high energy content of the bleed air obtained, for example, from main engines, the heat transfer is limited by the comparatively low heat transfer coefficient of air such that the deicing still cannot always be precisely controlled and is predominantly ensured by excess bleed air. In this case, excess bleed air that contains energy irreversibly escapes into the surroundings together with part of the energy generated by means of fuel.
In the development of modern commercial aircraft, there is a general trend to realize ecologically responsible solutions for minimizing the environmental consequences of industrial processes and products over their entire life cycle and to further reduce the costs. Future aircraft should be more economical, quieter and cleaner than today's commercial aircraft.